Timer for airplane engines



y 1933- w. E. SCHWARZMANN TIMER FOR AIRPLANE ENGINES Filed. Aug. 15, 19-52 2 Sheets-Sheet l EUEELHUX TOR Awe/2026174 w/f m zs BY Q. xi 62mm ATTORNEY July 11, 1933. W S HW Z NN 1,917,907

TIMER FOR AIRPLANE ENGINES Filed Aug. 13, 1932 2 Sheets-Sheet 2 Patented July 11 1933 UNITED STATES PATENT OFFICE WOLFGANG E. SCHWARZMANN, OF LONGMEADOW, MASSACHUSETTS, ASSIG-NOR TO UNITED AMERICAN BOSCH CORPORATION, OF SPRINGFIELD, MASSACHUSETTS, A

- CORPORATION OF NEW YORK TIMER FOR AIRPLANE ENGINES Application filed August 13, 1932. Serial No. 628,618.

I timers and particularly timers in the form of dual interrupter-distributor units for internal combustion engines.

An object of the invention is to provide a compactunit of this kind so as to save space and permit the use of additional apparatus with an internal combustion engine. Preferably theinventionisintended for airplane engines,which require the greatest possible saving in weight of their accessories.

Numerous airplane engines are now equipped with two magnetos for ignition and the magnetos have independent drive shafts. Sometimes the magnetos are on the same side of the engine and in other instances they are disposed on different sides. Such an arrangement, of course, takes up a great deal of room and makes difficult the location of other auxiliary apparatus; for instance, the generator for. starting and furnishing current for lighting the airplane. The invention herein set forth removes these drawbacks because the construction of the inter rupter distributor unit enables it to be substitutedfor the two magnetos; it occupies the position of one and makes the space formerly needed for the other available for the mounting of some other appliance. Wi h this improved timer on airplane engines ignition can be produced thereby in combination with a coil or coils energized by current drawn from the battery forstarting the engine.

A further object of the invention is to pro vide a timer that can be actuated in the same way as a magneto, is not materially different in form and is as restricted in size, and weight as operating conditions permit.

' A further obj ect'of the invention is to provide a dual timer designed so as to save both length and width and to facilitate the support of the device in working position and decrease the length of the drive shaft needed.

Other objects and advantages will appear as the following description proceeds and the novel features will be pointed out in the ap pended claims. A preferred embodiment of the invention is illustrated in the accompanying drawings, but changes can, of course, be made in various ways without, departing from the principle of the invention or exceeding the scope of the terms in which the claims are expressed.

On the drawings: Fig. l is an, end view partly in section showing a timer according to this invention;

Fig. 2 is a side view and Fig. 3 is a top view thereof; and

Fig. 4 is a horizontal section taken in the plane of the drive shaft adjacent the lower end of the unit.

On the drawings, the same numerals identify the same parts throughout. The numeral 1 indicates a supporting casing which may be in one piece and is provided at one extremity with a flange 2 to enable it to be secured to the frame of the engine by which it is to be carried. The cas ing 1 supports a pair of sockets 3 and each of these sockets receives the lower end of the housing of a combined timer and distributor indicated at 4, The casing 1 is, of course, hollow and the sockets 3 are located one at each side at different points along the length of the casing measured from end to end so that a transverseline passing through the middle of the two sockets will extend diagonally with reference to the length of the casing. This enables a saving in both length and width to be effected. The casing does not need to be as longas it would be if the sockets were in longitudinal alinement and it also does not have to be as wide as it would be if the two sockets were directly opposite each other on the two sides of the casing. Each of the sockets, which are open at their upper ends, is lined with a flanged bushing 5 in which the lower extremities 6 of the housing 4 are received. These extremities are reduced in diameter so that the upper parts of'the housings 4 can rest upon the outer ends of the bushings 5. i

The shafts 7 for operating the interrupter and distributor in each housing are arranged in bearings in the housings 4 and are disposed in vertical position. They project downward from the reduced lower extremities 6 in position to be rotated by a single shaft 8. This shaft 8 has worm gears 9 with hubs 10 011 the shaft 8 and each worm gear meshes with a similar gear shown at 11 on the shaft 7. The gears 11 have hubs 12 by which they are pinned to these shafts.

With this construction, the rotation of the shaft 8 will turn the two shafts 7 and bring about operation of the dual timer unit. Each of the housings 4 will contain a suitable interrupter or circuit breaker surmounted by a distributor including fixed terminals connected by high tension leads to the spark plugs of the engine and a rotor to close the circuit to each plug in turn. The details of the construction of the timer and distributor in each housing 4 is not part of this invention and need not be more fully described, since the invention relates more particularly to the method of mounting the two housings 4 with respect to the supporting casing 1 and the diminution in size and weight which is thus afl'orded.

The shaft 8 turns in ball bearings 16 in the two ends of the casing 1; and the end of this casing remote from the body of the engine may be closed by a plate 13 and bolts 14, the outer heads of which are perforated to receive a lock wire 15. The ball bearings men tioned are indicated at 16 and the shaft 8, of course, is geared to run at the necessary ratio with respect to one of the shafts of the engine so that the ignition will take place in the sequence desired.

' The circuit breaker of interrupter may be disposed in the lower part of each housing 4 and these housings may be provided at the top with a hollow head or cap 17 of insulation which encloses the parts of the distributor. The heads are held in place by means of spring clamps 18 pivotally connected to the outside of the housings 4 adjacent the top, the upper ends of these clamps being hookshaped to engage the ends of a loop strap 19 so as to hold the heads 17 in place. The clamps 18 are flexible and can easily be disengaged from the elements 19 to permit the removal of the heads and the inspection of the distributors and interrupterswithin the housings 4. Each housing has an external arm 20 to permit the'shifting of the housing within the bushing and thus advance or retard the instant of sparking. The two arms can be connected'tobe actuated together. Each of the housings may also be provided with an exterior insulated binding post or bushing 21 for the attachment of one end of the primary coil which is thus connected to the circuit breaker inside of the housing.

Each housing is detachably secured in the sockets 3 by means comprising a circumferential groove 22 in the reduced lower extremity 6 to retain the timer in the bushing and at the same time to hold the bushing in the socket 3 while permitting the removal of the housing when necessary. The socket 8 and bushing are provided with registering threaded holes to receive a sleeve nut 23 within which is a plunger having a head 24, the outer end of the plunger bearing a knob 25. Inside of the sleeve nut is a spring 26 which impels the head 24 into the groove 22. This head may be conical in shape and the groove may receive a block 27 with a conical recess to be engaged by the head 24. By this means the housings 4 will be retained in the bushings 5, but can be lifted out whenever the knob 25 is grasped and the head 24 is withdrawn. The member 27 can be mounted loosely in the groove 22 or it can be fixed therein and the seat in the member which receives the head 24 can be made of sufficient length to permit the movement of the housings by means of the arms 20. Also by screwing back the sleeve nut 23, either of the housings can at any time be disengaged and removed from the casing 1.

This dual timer unit thus gives a. reduction in both length and width; rendering it more adaptable for use, more easily supported and more stable in operation because the over hang of the shaft 8 or extent to which such shaft mustproject from the body of the em gine is likewise decreased. The moving parts in each housing can also be rotated in the same direction; see particularly Fig. 4. Both timer arms 20 can be joined for advancing or retarding the spark in unison and the problem of servicing is rendered easy because the interrupter-distributors can not be as sembled in the wrong position. The parts are further interchangeable. A. single unit of this sort takes the place of two magnetos and. makes the second drive shaft usually needed for two magnetos available to operate a lighting generator. The weight of the dual unit itself combined with the weight of such a generator is no more than the weight of two magnetos without the generator. The arrangement of the sockets 3 and housings 4 in off-set position with respect to both the longitudinal and transverse axis of the casing 1 so that a line joining the sockets 3 is diagonal to the shaft 8 is especially advantageous because of the saving in length, width and weight which this design affords. This unit can be employed without radio shields or such shields eanbe added if desired.

The type of distributor head 17 and parts inside same which are mounted upon each housing 4 may be varied; and while I show and, describe one form herein, the distributor head with radio shield as disclosed in'my copending application, Serial No. 628,072, for patent on ignition timers filed even date herewith may be snbstituted if desired.

The invention having been described, what i is claimed is:

i 1. A dual ignition unit comprising a casing and a pair of housings each adapted to contain an interrupter and a distributor mounted on said casing, one on each of the opposite the casing.

sides at different points along the length of 2. 'A dual ignition unit comprising a casing with sockets on each side of its longitudinal aXis, the upper ends of said sockets being open and an interrupter-distributor housing supported in each of said sockets.

3. A dual ignition unit comprising a casing with sockets on each of its opposite sides, the upper ends of said sockets being open and an interrupter distributor housing supported in each of said sockets, said sockets being disposed in diagonal alinement with respect to the length of thecasing.

4. A dual ignition unit comprising a casing, a shaft supported in the casing, a pair of worm gears on said shaft, a pair of shafts one at each of the opposite sides of the drive shaft, and'in diagonal alignment with respect thereto for operating an interrupter and distributor and a gear wheel on each of the driven shafts meshing with one of the gear wheels on the drive shaft whereby the drive shafts can be turned in the same direction.

. 5. A dual ignition unit comprising a casing having a pair of sockets one on each of the opposite sides of the casing and in diagona1 alinement with respect to the length of the casing, a drive shaft arranged longitudinally ofthe casing and passing between the sockets, a driven shaft in each of the sockets and gearing connecting the driven shaft to the drive shaft to be turned by the latter in the same direction.

6. A dual ignition unit comprising a single casing, a pair of interrupter-distributor housings adjustably mounted on the casing, and arms attached to each of said housings and adapted to be connected to move said housings in unison.

7 An ignition unit comprising a casing having an open-ended socket and a bushing having a flange on its outer end in said. socket and a timerdistributor housing having one end received in said socket, and means mounted in the socket for retaining the bushing and detachably holding the housing in position.

8. An ignition unit comprising a casing having an open-ended socket with a bushing therein, a housing for an interrupter-distributor having a reduced end received within the bushing, said end having a groove, a hollow sleeve nut mounted in the side of the socket and engaging the bushing, a springpressed plunger in said nut with a stem extending through the end thereof and having a knob on its outer end and bearing a head on its inner end to cooperate with said groove and prevent removal of the socket except when the plunger is withdrawn.

9. An ignition unit comprising a casing having an open-ended socket and a bushing having a flange on its outer end in said socket and a timer distributor housing having one end received in said socket, and means mounted in the socket for engaging the housing and bushing and detachably holding the housing in position.

10. An ignition unit comprising a casing having an open-ended socket with a bushing therein, said bushing having a flanged outer end engaging the rim of the socket, a housing for an interrupter-distributor having a reduced end received within the bushing, said end having a groove, a hollow sleeve nut mounted in the side of the socket and engaging the bushing, a spring-pressed plunger in said nut with a stem extending through the end thereof and having a knob on its outer end and means at the inner end of the plunger to cooperate with said groove and prevent removal of the casing except when the plunger is withdrawn.

11. An ignition unit comprising a casing having open-ended socket with a bushing therein, a housing for an interrupter-distributor having a reduced end received within the bushing, said end having a groove and means comprising a hollow sleeve nut and a springpressed plunger in said nut carried by the socket to engage the bushing and housing and detachably secure the housing in said socket.

In testimony whereof I aflix my signature.

WVOLFGANG E. SOHVVARZMANN. 

